Fouling Monitoring on Process Centrifugal Compressors

Abstract Oil and gas plants handle large quantities of gas through the deployment of centrifugal compressors. For this reason, they can be considered critical machines which can cause considerable loss of production and unexpected failures, if affected by fouling phenomenon. This brings to the need of continuous condition monitoring, which can allow for early detection of performance degradation and allow for unplanned outages of the machines. This work aims to present a proactive methodology for monitoring the status of the compressor fouling through a combination of variables. These factors can predict the amount of fouling expected within rotating equipment with a reasonable amount of certainty. Thanks to a set of specific "key indicators", it is possible to comprehend when the fouling can become a severe risk for the machine operability and consequently for the plant availability. The developed predictive methodology has been implemented in some operating sites, where it helps maintenance engineers to detect and manage the fouling phenomenon. The starting point of the study is to select, within the set of sensors available from remote monitoring, specific thermodynamic and vibration parameters. They are then used to build ad hoc KPIs that can enhance deep focus on compressor performance during operation. Combining both raw parameters and KPIs, it can be identified an overall picture of the health status of the compressor in term of fouling deposition. During the monitoring check, if most of the indicators are highlighting a combination of degradation of mechanical and thermodynamic performances, the probability of an ongoing fouling phenomenon is high and thus the engineers need to find out mitigations and eventually corrective actions. The developed methodology has been already applied to onsite compressors in order to detect possible fouling phenomenon. This method allows to constantly monitor the fouling criticality avoiding unprevented stops of the equipment for visual checks. The engineers, based on the results of these indicators, can evaluate the best timing and method aimed at maintaining compressor required performance. Thanks to this approach, it is possible to intervene before the situation gets worsening. Indeed, working with a fouled compressor, not only increases the probability of an unexpected failure, but reduce efficiency in operation. A decrease of performance means an increase of specific power consumption, which has an economic impact. Moreover, applying this methodology in oil and gas plants, can be beneficial also for the environment as it results in savings of CO2 emissions, as clean compressors need less power than a fouled one. The methodology innovative feature is the ability to monitor and early detect fouling phenomena from remote, permitting to engineer the inspections related to fouling with a combination of selected "key indicators". Applying this methodology systematically can enable a reduction of power consumption along with reduction of CO2 for a rotating machine. Also, the early detection of fouling phenomenon can reduce the probability of unexpected failures.